Telephone system.



E. G. GODFREE.

TELEPHONE SYSTEM.

APPLICATION FILED SEPT. 30. 1915.

2 SHEETS-SHEET l.

Patented Apr. 3, 1917.

E. G. GODFREE.

TELEPHONE SYSTEM.

APPLICATION man SEPT. 30. was.

Patented Apr. 3, 1917.

2 SHEETS-SHEET Z.

Altto'rney.

rinrrnn 1? PATENT @FFKEE,

TELEPHONE SYSTEM.

Specificationof Letters Patent.

. Patented Apr. 3, 1917.

Application filed September 30, 1915. Serial No. 53,336.

To all whom it may concern:

Be it known that I, ERNEST GRAHAM G01)- rnnn, a citizen of the Commonwealth of Australia, residing at Keighley, Sandringham Road, Sandringham, near Melbourne, in the State of Victoria and said Commonwealth, have invented Improvements Relating to Telephone Systems, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to telephone systems and has particular reference to systems or the kind in which means are provided to enable the number of calls made by subscribers to be recorded. A system of this kind disclosed in the specification of my prior Patent No. 1,111,742 dated September twenty-ninth 191 1 comprises means whereby the establishment of communication between two subscribers by way of the exchange causes the circuit of electromagnetic recorders or meters at the exchange to be closed so that the latter become operative and record a call, whereupon the circuit is broken, thereby avoiding waste of current and allowing the meters to return to their normal position ready to operate when the next call is made. The chief objects of the present invention are to enable each subscriber to have the number of effective calls made by him automatically recorded at his own end of the line, to insure that although a number of subscribers to the system may answer calls at the same instant each call will be sepa rately registered at the exchange and also at the subscribers end, and to prevent the registration of more than one call when the exchange operator has inadvertently rung up a wrong number and has again inserted the calling plug and obtained the number required. It may here be mentioned that the recording mechanism at the exchange usually consists of a separate meter for each subscriber and a totalizing meter common to all the subscribers meters controlled by any one exchange operator.

According to the present invention means are provided for automatically registering each subscribers call at his own end of the line. For this purpose an electromagnetic call meter at the subscribers end of the line is energized by current in a circuit closed at the exchange by an electromagnetic switch having its energizing winding in the energizing circuit of the same subscribers exchange call meter. The closing of the subscribers exchange call meter circuit is efiected by an electro-magnetic switch the winding of which forms part of the exchange connections of the called subscriber, while the subsequent opening of the said meter circuit is effected by a multiple-winding electromagnetic switch or which the wind ing energized last is in a circuit which is not closed until the subscribers exchange meter and also the totalizing meter, if present, have operated. The multiple-winding electro-magnetic switch for opening the exchange meter circuit is preferably of the consequent-pole type disclosed in the specification of my prior Patent No. 1,111,742 of September 29th 1911', requiring all of its windings to become energized to actuate it but remaining in its actuated position so long as any one winding is energized. The multiple-windings are preferably three in number, one being in the common battery exchange circuit of the answered subscriber, the second in the common battery circuit of the called subscriber, and the third in a circuit which is closed immediately after the answered subscribers exchange call meter has registered his call. Each subscribers battery exchange circuit includes at the exchange a switch arm normally closing a gap in the line but adapted to open the gap, when the exchange meter circuit has been closed, and make contact with a terminal connected to the exchange meter circuit battery and thereby cause the call meter at the subscribers end of the line to become energized.

In order that the invention may be clearly understood and readily carried into elfect the same will now be described more fully with reference to the accompanying diagrammatic drawings Figure 1, the left hand part of which represents a subscribers station, while the remainder illustrates the relevant parts of the exchange apparatus and connections.

Fig. 2 illustrates a diagrammatic view of a portion of the circuit with additional elements for the purpose of overcoming possible objections to the meter at the subscribers end being permanently earthed in the man ner illustrated in Fig. 1.

In the arrangement illustrated in Fig. 1, B represents the 24-volt common battery at the exchange for supplying current to the speaking circuits, and BB in series supply current at volts to the meter circuits and together constitutes what may be termed the exchange meter circuit battery. P is an answering plug, and P a calling plug of an exchange operator. C is theswitch that normally closes a gap in the subscribers line A. D is the switch for opening the exchange meter circuit. F is the switch for closing the exchange meter circuit. G is a totalizing meter at the exchange. K is the subscribers meter at the exchange, and M is the subscribers meter at his own end of the line. indicates a cut-off relay, only the energizing circuit of which is here shown and described, the usual circuits and apparatus controlled thereby being omitted for the sake of clearness.

' The operation of the system will now be described. When the subscriber lifts his receiver R from its hook, the signaling lamp at the exchange glows and the exchange op erator inserts the plug P and ascertains what number the subscriber requires in the usual way. The insertion of the plug P in its jack establishes the following circuits: from the negative pole of the Qt-volt' common battery B through the wire 1) to the plu P and station and back by way of the line A and jack spring y" to the tip of the plug 1, thence by way of the continuation A of the line A to the switch arm 0 of the switch C, and thence through the contact 0 andalong the wire A to the supervisory relay L back to the earthed positive pole E of the battery. A second circuit is from the negative pole of the battery B through the winding (Z of the switch D, thence through the supervisory lamp L to the plug P and thence through the cut-off 'relay j to earth at E and also to earth through the subscribers exchange meter K. It will be understood that owing to the energizing of the relay L, the current in the second mentioned circuit divides at the point cl", one part passing by way of the relay switch arm Z and contact Z and the remainder, which passes through the lamp L, being so weak as not to cause the lamp to glow.

hen the exchange operator has ascertained what number the subscriber requires, he inserts the corresponding plug P, there by completing a circuit from thenegative pole of the battery B through the winding d of the switch D, thence through the supervisory lamp L to the plug P, and thence through the jack to earth. It is to be noted that the switch D is so constructed and arranged that the energizmg of both wmdmgs cljand d is insuflicient to move the switch described in the specification of my prior patent beforementioned.

Until the called subscriber lifts his receiver from its hook the supervisory relay switch arm Z is in its open position and the lamp L receives the full current, thus being caused to glow. \Vhen however the called subscriber lifts his receiver the speaking circuit is established and the supervisory'relay L is operated thus diverting some of the current from the lamp, which then ceases to glow. The shunt path established by the operation of the relay L contains the winding f of the switch F.

W hen the switch F is energized by current passing through its winding, the switch arm f is attracted and makes contact with the contact f thereby closing the following circuit;from the negative pole of the combined batteries B, B, through the winding ir of the totalizing meter or register G, along line 9 to the contact (Z of switch D, through the switch arm a to the winding it of a switch H, thence to the winding c'- of the switch C and thence to the above mentioned contact f and switch arm f of the switch F, whence the current passes along the line to the plug P, and thence by way of the wire is and through the subscribers exchange meter K to earth.

The combined voltage of the batteries B and B is suliicient to cause the totalizing meter G and the subscribers exchange meter K to operate and record a call.

hen the armature 7 of the meter K moves to actuate the counting device it also short-circuits a part of its winding and thereby reduces the resistance in the meter circuit above traced. The increased current then passing through the windings It and c of the switches H and C respectively causes these switches to immediately operate. The operation of the switch C resulting in the switch arm 0 making contact with the contact c closes a circuit which may be traced as follows :from the negative pole of the batteries B, B through the winding G" of the totalizing meter to the Contact (Z thence through the switch arm (Z and. the coils h and c to the contact 0", thence through the contact armc, along the wire A to the tip of the plug P, and thence along the line A to earth through the winding m of the subscribers meter M at the subscribers end of the line. The combined voltage of the bat teries B and B is suliicient to operate the meter M and the latter .therefore registers the subscribers call. The operation of the switch H, which occurssimultaneous] y with the operation of the switch C, causes the switch arm 71. to make contact with the contact 7L2, thereby completing the following circuit -from the negative pole of the battery B to the switch arm h and. contact If, thence through the winding d of the switch D and by way of the contact 9 and armature g of the exchange totalizing meter G to earth. The windings d and d of the switch D having become energized as already described, the three energized windings d, d and (Z are suiiicient ,to actuate the switch arm (Z thereby breaking the energizing circuit of the totalizing meter Gr, the switches H and C, and the subscribers exchange meter K. The switch arm (Z of the switch I) remains in its circuit breaking position until both plugs P and P are withdrawn, owing to the fact that any one switch winding while energized is suflicient to retain the arm in its circuit breaking position although it requires the three windings to move this arm into that position.

C" is a very high resistance which is preferably connected across the wires A and A in order to prevent a complete interruption of current at the contact 0 and switch arm 0.

Important features of novelty of the present invention may in conclusion be briefly emphasized as follows:

The provision of the "call meter M at each subscribers station and the operation of this meter as described enables each subscriber to know at any time for how many calls he will be charged.

The operation of both meters K and M as described enables the exchange authorities to know that whenever the exchange meter K is operated, the subscribers meter M is also operated.

The meter circuit closing switch F need not be of the consequent pole type but may be a simple form of electromagnetic switch.

The inclusion of the winding 72, of the switch H in the exchange meter circuit and of the gap at the switch H in the circuit of the winding d of the switch D insures that the exchange meters Gr and K are operated before the meter circuit can be broken by the switch D.

In the event of the exchange operator having called up a wrong number and caused the meter circuit to be closed at the switch F and subsequently opened at the switch D, the withdrawal of the calling plug and its insertion into the correct jack will not affect the switch arm d since the latter is able to be held in its circuit breaking position by the winding 03. Consequently the calling subscriber is not charged for two calls.

In the event of the exchange operator hav ing inserted two or more calling plugs at about the same time and of the called subscribers lifting their respective receivers at the same instant, the two separate calls will be separately registered by the operation of the respective meter circuits; for instance, one call will be registered as already described by the operation of the call meters shown in the drawing, and the other call will be registered in the same way by the operation of a similar separate call meter in a separate circuit branching (as by the wire from the totalizing meter G.

In the arrangement illustrated in Fig. 2 provision is made to overcome a possible objection to the meter M at the subscribers end of the line being permanently earthed as illustrated in Fig. 1.

M is the meter at subscribers end, and r is a contact fitted to the switch hook of the telephone. R is an electromagnet in the line circuit A d is an armature operated by the electromagnet It when receiver is taken 4 off the hook.

O is an electro-magnet of low resistance placed in the meter circuit at the exchange and is energized only when an eliectual call is being registered, and contacts 8 and s are in the line circuits A and A respectively. 8 is a contact on the front stop the armature of electro-magnet C and is for the purpose of connecting the battery S to the line A when the electro-magnet C is energized.

The operation of these additional features if included in the circuit would be as follows The receiver is taken from hook for the purpose of making a call, current flows over line circuits A and A magnet R is energized, and contact 0Z is opened.

Connections are made at the exchange and the subscriber desired is called and the automatic devices operate at the exchange, electromagnet G being in the meter circuit at the exchange is therefore energized and the armature carrying contacts 5, s and s is attracted. The battery S is impressed on the line and current flows from earth E at exchange through battery B, contact 8 line A, contact 7, contact 6Z5, meter M to earth at subscribers end.

Line A is opened temporarily at s and magnet R- is de'elnergized. After the meters at the exchange have operated all apparatus resume normal position, that is,-as if the recording devices were not in the circuit and the earth at the subscribers end is disconnected by the energization of the electromagnet It.

By the operation of the device in this manner there is no earth on the line when the calling and answering subscriber are speaking, the earthing of the line taking place temporarily and while the subscribers meter registers a call the earth at the subscribers end of the line being then automatically disconnected after the call is registered.

What I claim as my invention and desire to secure by Letters Patent is 1. In a telephone exchange system, substations, a central station, line circuits connecting said substations with the central station, a call meter at a sub-station, an electro-magnetic exchange call meter, and a relay atthe exchange having its energizing Winding included in the energizing circuit of said exchange meter and controll ngsaid sub-station meter over the line circuit of the associated sub-station. V

2."In a telephone exchange system, substations, a central station, line circuits connecting said sub-stations with the central station, callmeters'at said sub-stations, electro-magnetic call meters at the central office individual to the sub-stations, and a relay at the central station arranged to be energized in series with the winding of the central office meter of a given line to' complete the circuit of the sub-station meter of that line over the associatedline circuit. V

In a telephone exchange system, substations, a central station, line circuits connecting said substations with the central station, exchange circuits individual to each sub-station, exchange call meters individual to the sub-stations and energizing circuits therefor,-a single coil relay having its conv tacts included in the energizing circuit of an exchange call meter for control thereof and its energizing circuit controlled from an other sub-station, a. totalizing meter at the central station and an energizing circuittherefor, a multiple-winding relay at the central station operable only upon energization of allof its windings to open the energizing circuit of said exchange call meter, and means controlling the energization of One of the windings of said multiple-winding relays operable only upon the energization of the other of said multiple windings and said central station meters.

4. In a telephone exchange system, sub-' stations,a central station,.line circuits connecting saidsub-stations with the central station, a subscribers call meter situated at each sub-station and controlled over one member of the line circuit, a normally shunted resistanc in the other member of said line circuit, a call meter at the central station, and a relay at the central station arranged to be energized upon the operationof said centralstation meter and operable to open said shunt and energize said subscribers call meter over the first said-member of the line circuit.

5; In a telephone exchange system, substations, a. central station, line circuits connecting said. sub-stations with the central station, a central station call meter and energizing circuit therefor, means for closing said circuit for energizing said meter and causing it to operate, a multiple-Windingv relay-operable only upon the energization of all of its windings and arrangedto open the circuit of said meter, and a circuitclosingrelay having its winding included in the energizing circuit of the meter and operable only upon operation of the meter to complete the energization of one of the after the other of said windings have be come energized, said multiple-winding relay being arranged to maintain the meter circuit open during the energization of any one of its windings.

6. In a telephoneexchange system, substations, a central station, line circuits connecting said substations with the central station, a call meter at each sub-station controlled from the exchange over one member of the line circuit and a grounded circuit, means at the central station for interconnecting said sub-stations, a relay at each substation operable to open said ground circuit at its associated sub-station and arranged to be normally energized during the connec tion of said interconnecting means with its associated sub-station, and automatic means operable upon the completion of a talking circuit connection between said sub-station and another sub-station to momentarily disable said sub-station relay and energize the call meter of the associated sub-station over said grounded circuit.

7. In a telephone exchange system, a plurality of subscribers lines, link circuits for interconnecting the same, a call meter and energizing circuit therefor, and automatic switching means operable only upon the concurrence of (1) a connection of said link with a calling subscriber, (2) a connection of said link with the line circuit of a called subscriber who has answered and (3) the energization of said call meter, to disable the said meter energizing circuit and maintain said circuit disabled during the continuance of any one of said three conditions.

8. In a telephone exchange system, a plurality of sub-stations connected with a central station, means at the central station for interconnecting the sub-stations, a call meter at each sub-station, a call meter at the central station for each sub-station, a totalizing meter at the central station common to a plurality of sub-stations, a meter energizing circuit associated with said interconnecting means and arranged to be connected in common with said totalizing meter and the individual call meters of a calling sub-station with which its associated interconnecting means is connected for energizing said meters, and a unitary automatic switching device associated with each interconnecting means operable only upon the concurrence of (1) a connection of its associated interconnecting means with a calling subscriber, (2) a connection of the same interconnecting means with the line of a called subscriber who has answered and (3) the energization of said meters, to disable the said meter energizing circuit and maintain said circuit disabled during the continuance of any one of said three conditions.

9. In a telephone exchange system, subscribers sub-stations and line circuits therefor, switching means for interconnecting the same, answering and calling supervisory circuits for said switching means, a call meter and energizing circuit therefor, and electromagnet switching means included in all of said circuits and operable only upon the concurrent energization of all of said circuits to disable said call meter energizing circuit and maintain the same disabled during the energization of any one of said circuits.

10. In a telephone exchange system, subscribers lines, switching means for interconnecting the same, answering and calling supervisory circuits for each of said switching means, a totalizing call meter associated with said switching means, subscribers individual call meters, one at the subscribers end and one at the exchange end of each subscribers line, a meter energizing circuit associated with each switching means arranged to energize the totalizing meter of its associated switching means and the individual meters of a line with which said switching means is connected, a circuit closing relay associated with each switching means operable upon the energization of the said calling supervisory circuit to close the said meter energizing circuit, and a circuit disabling relay associated with each switching means having three energizing windings and operable only upon the concurrent encrgization of all said windings to disable the said associated meter energizing circuit and maintain the same disabledduring the energization of any one of said windings, one of said windings being included in the associated answering supervisory circuit, another included in the associated calling supervisory circuit and the third included in the associated meter energizing circuit.

In testimony whereofI aflix my signature in the presence of two witnesses.

ERNEST GRAHAM GODFREE.

Witnesses A. EDWARDS, SIDNEY HENDLEY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. 0." 

